Absorption of electromagnetic radiation by a cylindrical metal particle

The cross section of the absorption of electromagnetic radiation by a cylindrical metal particle is calculated. The calculation is performed in the low-frequency limit, in which the contribution of eddy currents to the absorption dominates, and for comparatively small particles (with radii of ≈10 nm), which allows us to neglect the skin effect. The case when the mean free path of electrons in the metal bulk substantially exceeds the radius of the cylindrical particle is considered in detail. The specific absorption cross sections for spherical and cylindrical particles are compared.     

Effect of electron reflection from the surface on the electromagnetic properties of cylindrical particles

The cross section of the absorption of a magnetic field by a cylindrical metal particle is calculated. The general case when the ratio of the electron mean free path to the particle transverse size may take arbitrary values is considered. The boundary conditions imply the mixed mirror-diffuse reflection of electrons from the inner surface of the particle. The limiting cases are considered and results obtained are discussed.     

Interaction of electromagnetic radiation with a cylindrical particle of finite length

The magnetic absorption cross section of a cylindrical metal particle of finite length is calculated. A general case is considered when the ratio of the transversal dimension of a particle to its length may take arbitrary values. Diffuse reflection of electrons from the internal surface of a particle is chosen as the boundary condition for the problem. Limiting cases are considered, and the results are discussed.     

Absorption of electrical energy by a fine cylindrical metal particle

The absorption cross section for the energy of an electric field aligned with the symmetry axis of a cylindrical metal particle is calculated. The radius of the particle is assumed to be much smaller than its length. As the boundary condition of the problem, diffuse reflection of electrons from the inner surface of the particle is taken. Limiting cases are considered, and the results obtained are discussed.     

Absorption of electromagnetic radiation by a bimetallic cylindrical particle of finite length

The absorption cross section of electromagnetic radiation is calculated for a bimetallic cylindrical particle of finite length. A general case is considered, where the ratio of the radius of the particle core to the particle radius and the ratio of the radius of the particle to its length can take arbitrary values. The conditions of diffuse reflection of electrons from the internal and external surfaces of the metal shell of the particle and from its faces are used as the boundary conditions of the problem. The effect of the ratio of the radius of the core of a bimetallic cylindrical particle to the particle radius and the ratio of the radius of the particle to its length on the electromagnetic properties of the particle is analyzed.     

Electric-field energy absorption by a bimetallic cylindrical particle

The electric-field energy absorption cross section of a bimetallic cylindrical particle is calculated for an external ac electric field directed along the axis of the particle. The calculations are performed for arbitrary values of the ratio of the particle core radius to the particle radius. The reflection of electrons from the inner and outer surfaces of the metallic shell of the particle is assumed to be diffuse. The limiting cases are considered, and the results obtained are discussed.     

Effect of the character of conduction electron reflection on the electromagnetic properties of an inhomogeneous cylindrical particle

The cross section of magnetic absorption of a small elongated cylindrical particle with a dielectric core and metallic shell is calculated. The general case of an arbitrary value of the ratio of the dielectric core radius to the radius of the particle is considered. The condition of mixed (mirror-diffuse) reflection of conduction electrons from the boundaries of the metal layer of the particle is chosen as the boundary condition to the problem. The limiting cases are considered, and the results obtained are discussed.     

基于Mie散射理论的MgF_2颗粒散射特性研究

本文应用Mie散射理论对微球体颗粒光散射的性质进行了理论分析与数值计算,得到了吸收截面与波长,散射强度与散射角以及散射强度与参数x的关系。结果表明,入射波长在300~4800 nm,粒子的吸收截面都为零;当λ>4800 nm,吸收截面随着粒子半径的增大而增大。     

Internal electric field distribution within a micro-cylinder-shaped particle suspended in an absorbing gaseous medium

The present study is concerned with photophoresis of a microsized long cylinder-shaped particle suspended in an absorbing gas medium. To facilitate the analysis, an infinite cylinder subjected to an intensive light beam is considered as the physical model. The electromagnetic energy can be absorbed by the particle and turned into thermal energy heating surface unevenly, which results in a net momentum transfer between gas molecules and the particle to drive particle in photophoretic motion. Effects of the governing parameters on the absorbed energy distribution in the cylindrical particle are investigated. The results demonstrate that increasing either the radius or absorptivity of the cylinder enhances the energy absorbed on the illuminated side and tends to generate positive photophoresis; while an increase in the refractivity of the particle tends to enhance the internal electric field intensity and shift the absorption peak on the shaded side toward the particle center. Increase in medium absorptivity reduces the energy reaching at the particle, which significantly degrades the level of energy absorption and therefore weakens the photophoretic mobility of the particle. It is also found that, at the same conditions, the source function peaks in long cylinder-shaped particles are generally lower than those in spheres due to the weaker light refraction of the cylindrical shape.     

Influence of the skin effect on the absorption of electromagnetic radiation by a fine metal particle

The cross section of absorption of electromagnetic radiation by a fine spherical metal particle is calculated. The influence of the skin effect on the absorption cross-section is estimated for an arbitrary ratio between the free path and size of the particle. The results of this work are compared with those obtained earlier in the framework of classical electrodynamics. It is shown that taking into account the kinetic effects modifies essentially the known data for the skin effect in a spherical particle.     

Calculation of the electromagnetic absorption by a small metal particle with a two-parameter kinetic equation

The behavior of the magnetic dipole absorption cross section in a small metal particle is considered. A modified kinetic equation with the collision integral taking into account the deviation of the properties of metals at low temperatures from the Wiedemann-Franz law is solved. Diffuse reflection of electrons from the sample surface is considered. The dependence of the absorption cross section of a particle on the parameter describing the deviation from the Wiedemann-Franz law is analyzed.     

有机材料反饱和吸收特性分析

从能级角度出发,结合入射激光脉宽对粒子吸收方面的影响,用速率方程模拟了各能级粒子数的瞬时变化关系,给出了激光脉宽与能级寿命可比拟时反饱和吸收的动态解,表明粒子在能级上的分布情况。用C60和HITCI(1,1′,3,3,3′,3′hexa methyl lindo tricarbocyanine Iodide)的实验参数理论模拟了激发态吸收截面大于基态吸收截面时透射率随光强的变化关系,用以说明大的上能级吸收截面可以抑制光强过大时引起的饱和吸收,增强材料的非线性光限幅特性。     

General derivation of the total electromagnetic cross sections for an arbitrary particle

This work concerns a common problem in electromagnetic scattering; calculation of the total scattering, extinction, and absorption cross sections for an arbitrary particle. Typical expressions for the cross sections are obtained in terms of the vector spherical wave function expansions for the incident and scattered waves. The unique aspect of this work is that the derivation is carried out specifically without use of the far-field zone approximation. The resulting expressions, valid at any distance, exactly match those obtained from the far-field approximation. This demonstrates that the cross sections are independent of the distance from the particle at which they are calculated as one would expect from energy conservation. Numerical simulations of the near and far-field zone energy flows due to a spherical particle are presented to illustrate several implications of this result.     

Absorption Cross Section of Einstein-Maxwell Dilation Axion Black Hole for Dirac Particles

The absorption cross section of the Einstein-Maxwell Dilaton Axion (EMDA) black hole for Dirac particles is investigated. It is shown that the absorption cross section decreases as both the v and the absolute value of the dilaton increase, but it increases as the mass of the particle increases. It is also shown that the absorption cross section for the massless Dirac particles is 1/8 of the area of the horizon, which may be an universal property for minimally coupled massless Dirac particles.     

Retardation-induced plasmon resonances in coupled nanoparticles

We study the coupling induced by retardation effects when two plasmon-resonant nanoparticles are interacting. This coupling leads to an additional resonance, the strength of which depends on a subtle balance between particle separation and size. The scattering cross section and the near field associated with this coupled resonance are studied for cylindrical particles in air and in water. Implications for surface-enhanced Raman scattering and nano-optics are discussed.     

On the magnetic dipole absorption of electromagnetic radiation by a fine conducting particle

The cross section of absorption of electromagnetic radiation by a fine spherical conducting particle is estimated in terms of the classical kinetic theory of electrical conduction. The mixed diffuse-specular mechanism of charge carrier reflection from the sample boundary is considered. A correlation between the coefficient of specular reflection and the absorption cross section at different temperatures is analyzed.     

Absorption of electromagnetic radiation by an inhomogeneous spherical particle

The cross section of absorption of electromagnetic radiation by an inhomogeneous spherical particle is calculated. The general case of an arbitrary value of the ratio of the particle radius to the radius of the dielectric core is considered. The condition of diffuse reflection of electrons from the inner and outer surfaces of the metal layer of the particle is taken as the boundary condition of the problem. The limiting cases are considered and the results obtained are discussed.     

Temperature effects on the absorption cross section of a small conductive particle

Temperature effects on the absorption cross section of a small conductive spherical particle were investigated. Calculations were performed in terms of the kinetic approach for the case where the contribution of eddy currents to the absorption dominated and provided that the particle size was small compared to the skin depth. The latter condition allows the skin effect to be disregarded.     

Absorption Cross Section of Static Einstein-Maxwell Dilation Axion Black Hole for Scalar Particles

The absorption cross section of the static Einstein-Maxwell dilaton axion （EMDA） black hole for scalar particles is investigated. It is shown that the ratio of the absorption cross section of the EMDA black hole to that of the Schwarzschild black hole decreases as the absolute value of the dilaton increases, and it becomes zero as the dilaton tends to its extremal value. It is also shown that the absorption cross section decreases as both the v and the absolute value of the dilaton increase, and it decreases as the mass of the particle decreases.     

The effect of the character of electron reflection on the electromagnetic properties of an inhomogeneous spherical particle

The magnetic absorption cross section of a small spherical particle with a dielectric core and a metallic shell is calculated. The general case is considered when the ratio of the radius of the dielectric core to the total radius of the particle may take arbitrary values. The condition of specular-diffuse reflection of conduction electrons from the surfaces of the metal layer of the particle is chosen as the boundary conditions of the problem. The limit cases are considered, and the results are discussed.